Fast initial link setup discovery frames

ABSTRACT

A method for fast initial link setup (FILS) for use in a wireless station, is disclosed. The method comprises receiving a FILS discovery (FD) frame from an access point (AP). The FD frame comprises an FD frame control field and FD frame contents. The FD frame control field comprises a service set identifier (SSID) indicator, indicating whether an SSID field in the FD frame contents contains a full SSID or a short SSID and an SSID length field, indicating a size of the full SSID or the short SSID contained in the SSID field in the FD frame contents. The method further comprises determining whether to associate with the AP based on the received FD frame; and on a condition the determination is positive, the method further comprises transmitting an association request frame to the AP. A wireless station is also disclosed.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/933,401, filed Jul. 2, 2013, which claims the benefit of U.S.Provisional Patent Application No. 61/667,600, filed Jul. 3, 2012, andU.S. Provisional Patent Application No. 61/695,177, filed Aug. 30, 2012,which are incorporated by reference as if fully set forth herein.

BACKGROUND

A wireless local area network (WLAN) in the infrastructure basic serviceset (BSS) mode has an access point (AP) for the BSS, and one or morestations (STAs) associated with the AP. The AP typically has access toor interfaces with a distribution system (DS) or another type ofwired/wireless network that carries traffic in to and out of the BSS.Traffic to STAs that originates from outside the BSS arrives through theAP and is delivered to the STAs. Traffic originating from STAs todestinations outside the BSS is sent to the AP to be delivered to therespective destinations. Traffic between STAs within the BSS may also besent through the AP where the source STA sends traffic to the AP and theAP delivers the traffic to the destination STA. Such traffic betweenSTAs within a BSS is really peer-to-peer traffic. Such peer-to-peertraffic may also be sent directly between the source and destinationSTAs with a direct link setup (DLS) or a tunneled DLS (TDLS). A WLAN inindependent BSS mode (IBSS) has no AP and STAs communicate directly witheach other.

In an infrastructure BSS, a STA performs a scanning procedure todiscover an appropriate AP/network to establish a WLAN link, usually viaan association procedure. There are two basic scanning modes: passivescanning and active scanning.

With the passive scanning mode, the AP periodically transmits beaconframes to provide AP/network information to the STA. The beacon supportsvarious functions in the system by providing an AP advertisement with aBSS identifier (BSSID), synchronization of the STAs in the BSS,capability information, BSS operation information, system parameters formedium access, transmit power limits, etc. In addition, the beacon maycarry many optional information elements.

With the active scanning mode, the STA actively generates and transmitsa probe request frame to the AP, receives a probe response frame fromthe AP, and processes the probe response frame to acquire the AP/networkinformation.

FIG. 1 shows a general frame format for a beacon frame 100, whichincludes a medium access control (MAC) header 102, a frame body 104, anda frame check sequence (FCS) field 106. The MAC header 102 includes aframe control field 110, a duration field 112, multiple address fields114-118, a sequence control field 120, and a high throughput (HT)control field 122.

The frame body 104 includes mandatory fields and information elements(IEs), including, but not limited to (not shown in FIG. 1): a timestampfield, a beacon interval field, a capability field, a service setidentifier (SSID) field, a supported rates field, and one or moreoptional IEs, such as BSS load information. The BSS load informationindicates the level of traffic loading at the BSS, and may include fiverelevant IEs: BSS load, including STA count, channel utilization, andadmission capability; BSS available admission capacity; quality ofservice (QoS) traffic capability; BSS average access delay; and BSSaccess category (AC) access delay. With the mandatory and typicaloptional IEs, beacon frames may be over 100 bytes long. In a typicalenterprise environment, the beacons are approximately 230 bytes long.

A goal with fast initial link setup (FILS) is to support an initial linksetup time for STAs within 100 ms and to support at least 100 non-APSTAs simultaneously entering the BSS and fast link setup within onesecond. Because beacons may be used to provide information about the APto the STAs at the beginning of the initial link setup process, beaconsmay include information to facilitate a fast link setup to satisfy thespecified functional requirements.

The FILS process consists of five phases: (1) AP discovery; (2) networkdiscovery; (3) additional timing synchronization function (TSF); (4)authentication and association; (5) higher layer IP setup.

SUMMARY

A method for fast initial link setup (FILS) for use in a wirelessstation, is disclosed. The method comprises receiving a FILS discovery(FD) frame from an access point (AP). The FD frame comprises an FD framecontrol field and FD frame contents. The FD frame control fieldcomprises a service set identifier (SSID) indicator, indicating whetheran SSID field in the FD frame contents contains a full SSID or a shortSSID and an SSID length field, indicating a size of the full SSID or theshort SSID contained in the SSID field in the FD frame contents. Themethod further comprises determining whether to associate with the APbased on the received FD frame; and on a condition the determination ispositive, the method further comprises transmitting an associationrequest frame to the AP.

A wireless station comprising a receiver, transmitter, and processor isalso disclosed. The receiver is configured to receive a FILS discovery(FD) frame from an AP. The FD frame comprises an FD frame control fieldand FD frame contents. The FD frame control field comprises a serviceset identifier (SSID) indicator, indicating whether an SSID field in theFD frame contents contains a full SSID or a short SSID of the AP; and anSSID length field, indicating a size of the full SSID or the short SSIDcontained in the SSID field in the FD frame contents. The processor isconfigured to determine whether to associate with the AP based on thereceived FD frame. The transmitter is configured to transmit anassociation request frame to the AP, on a condition that thedetermination by the processor is positive.

BRIEF DESCRIPTION OF THE DRAWINGS

A more detailed understanding may be had from the following description,given by way of example in conjunction with the accompanying drawings,wherein:

FIG. 1 is a diagram of a beacon frame format;

FIG. 2A is a system diagram of an example communications system in whichone or more disclosed embodiments may be implemented;

FIG. 2B is a system diagram of an example wireless transmit/receive unit(WTRU) that may be used within the communications system illustrated inFIG. 2A;

FIG. 2C is a system diagram of an example radio access network and anexample core network that may be used within the communications systemillustrated in FIG. 2A;

FIG. 3 is a diagram of a measurement pilot frame format;

FIG. 4 is a diagram of a short beacon frame format;

FIG. 5 is a diagram of an access network options information elementformat for use in a FD frame;

FIG. 6 is a diagram of a neighbor AP information element format for usein a FD frame;

FIG. 7 is a diagram of a robust security network element (RSNE) for usein a FD frame;

FIG. 8 is a diagram of a fixed-length optimized RSNE for use in a FDframe;

FIG. 9 is a diagram of a variable-length optimized RSNE for use in a FDframe;

FIG. 10 is a diagram of a fixed-length bit-map coding for an optimizedRSNE for use in a FD frame;

FIG. 11 is a diagram of a fixed-length two octet optimized RSNE for usein a FD frame;

FIG. 12 is a diagram of a two octet optimized RSNE with a RSNcapabilities field for use in a FD frame;

FIG. 13 is a diagram of HT physical layer-specific information elementfor use in a FD frame;

FIG. 14 is a diagram of very high throughput (VHT) physicallayer-specific information element for use in a FD frame;

FIG. 15 is a diagram of a FD frame control field format;

FIGS. 16A-16B are diagrams of exemplary FD frame SSID designs;

FIG. 17 is a diagram of a FD frame capability information item format;

FIG. 18 is a diagram of a FD frame security information item format;

FIGS. 19A-19B are diagrams of a variable length FD frame securityinformation item format;

FIG. 20 is a diagram of a FD frame AP's next TBTT information itemformat;

FIG. 21 is a diagram of a FD frame neighbor AP information item format;

FIG. 22 is a diagram of an exemplary FD frame body format;

FIG. 23 is a diagram of an extendable FD frame body format;

FIG. 24 is a diagram of a FD frame in a public action frame format;

FIG. 25 is a diagram of a FD extension frame format with a separateframe control field; and

FIG. 26 is a diagram of a FD extension frame format with a combinedframe control field.

DETAILED DESCRIPTION

FIG. 2A is a diagram of an example communications system 200 in whichone or more disclosed embodiments may be implemented. The communicationssystem 200 may be a multiple access system that provides content, suchas voice, data, video, messaging, broadcast, etc., to multiple wirelessusers. The communications system 200 may enable multiple wireless usersto access such content through the sharing of system resources,including wireless bandwidth. For example, the communications systems200 may employ one or more channel access methods, such as code divisionmultiple access (CDMA), time division multiple access (TDMA), frequencydivision multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrierFDMA (SC-FDMA), and the like.

As shown in FIG. 2A, the communications system 200 may include wirelesstransmit/receive units (WTRUs) 202 a, 202 b, 202 c, 202 d, a radioaccess network (RAN) 204, a core network 206, a public switchedtelephone network (PSTN) 208, the Internet 210, and other networks 212,though it will be appreciated that the disclosed embodiments contemplateany number of WTRUs, base stations, networks, and/or network elements.Each of the WTRUs 202 a, 202 b, 202 c, 202 d may be any type of deviceconfigured to operate and/or communicate in a wireless environment. Byway of example, the WTRUs 202 a, 202 b, 202 c, 202 d may be configuredto transmit and/or receive wireless signals and may include userequipment (UE), a mobile station, a fixed or mobile subscriber unit, apager, a cellular telephone, a personal digital assistant (PDA), asmartphone, a laptop, a netbook, a personal computer, a wireless sensor,consumer electronics, and the like.

The communications systems 200 may also include a base station 214 a anda base station 214 b. Each of the base stations 214 a, 214 b may be anytype of device configured to wirelessly interface with at least one ofthe WTRUs 202 a, 202 b, 202 c, 202 d to facilitate access to one or morecommunication networks, such as the core network 206, the Internet 210,and/or the other networks 212. By way of example, the base stations 214a, 214 b may be a base transceiver station (BTS), a Node-B, an eNode B,a Home Node B, a Home eNode B, a site controller, an access point (AP),a wireless router, and the like. While the base stations 214 a, 214 bare each depicted as a single element, it will be appreciated that thebase stations 214 a, 214 b may include any number of interconnected basestations and/or network elements.

The base station 214 a may be part of the RAN 204, which may alsoinclude other base stations and/or network elements (not shown), such asa base station controller (BSC), a radio network controller (RNC), relaynodes, etc. The base station 214 a and/or the base station 214 b may beconfigured to transmit and/or receive wireless signals within aparticular geographic region, which may be referred to as a cell (notshown). The cell may further be divided into cell sectors. For example,the cell associated with the base station 214 a may be divided intothree sectors. Thus, in one embodiment, the base station 214 a mayinclude three transceivers, i.e., one for each sector of the cell. Inanother embodiment, the base station 214 a may employ multiple-inputmultiple-output (MIMO) technology and, therefore, may utilize multipletransceivers for each sector of the cell.

The base stations 214 a, 214 b may communicate with one or more of theWTRUs 202 a, 202 b, 202 c, 202 d over an air interface 216, which may beany suitable wireless communication link (for example, radio frequency(RF), microwave, infrared (IR), ultraviolet (UV), visible light, etc.).The air interface 216 may be established using any suitable radio accesstechnology (RAT).

More specifically, as noted above, the communications system 200 may bea multiple access system and may employ one or more channel accessschemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. Forexample, the base station 214 a in the RAN 204 and the WTRUs 202 a, 202b, 202 c may implement a radio technology such as Universal MobileTelecommunications System (UMTS) Terrestrial Radio Access (UTRA), whichmay establish the air interface 216 using wideband CDMA (WCDMA). WCDMAmay include communication protocols such as High-Speed Packet Access(HSPA) and/or Evolved HSPA (HSPA+). HSPA may include High-Speed DownlinkPacket Access (HSDPA) and/or High-Speed Uplink Packet Access (HSUPA).

In another embodiment, the base station 214 a and the WTRUs 202 a, 202b, 202 c may implement a radio technology such as Evolved UMTSTerrestrial Radio Access (E-UTRA), which may establish the air interface216 using Long Term Evolution (LTE) and/or LTE-Advanced (LTE-A).

In other embodiments, the base station 214 a and the WTRUs 202 a, 202 b,202 c may implement radio technologies such as IEEE 802.16 (i.e.,Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000,CDMA2000 1×, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), InterimStandard 95 (IS-95), Interim Standard 856 (IS-856), Global System forMobile communications (GSM), Enhanced Data rates for GSM Evolution(EDGE), GSM EDGE (GERAN), and the like.

The base station 214 b in FIG. 2A may be a wireless router, Home Node B,Home eNode B, or access point, for example, and may utilize any suitableRAT for facilitating wireless connectivity in a localized area, such asa place of business, a home, a vehicle, a campus, and the like. In oneembodiment, the base station 214 b and the WTRUs 202 c, 202 d mayimplement a radio technology such as IEEE 802.11 to establish a wirelesslocal area network (WLAN). In another embodiment, the base station 214 band the WTRUs 202 c, 202 d may implement a radio technology such as IEEE802.15 to establish a wireless personal area network (WPAN). In yetanother embodiment, the base station 214 b and the WTRUs 202 c, 202 dmay utilize a cellular-based RAT (for example, WCDMA, CDMA2000, GSM,LTE, LTE-A, etc.) to establish a picocell or femtocell. As shown in FIG.2A, the base station 214 b may have a direct connection to the Internet210. Thus, the base station 214 b may not be required to access theInternet 210 via the core network 206.

The RAN 204 may be in communication with the core network 206, which maybe any type of network configured to provide voice, data, applications,and/or voice over internet protocol (VoIP) services to one or more ofthe WTRUs 202 a, 202 b, 202 c, 202 d. For example, the core network 206may provide call control, billing services, mobile location-basedservices, pre-paid calling, Internet connectivity, video distribution,etc., and/or perform high-level security functions, such as userauthentication. Although not shown in FIG. 2A, it will be appreciatedthat the RAN 204 and/or the core network 206 may be in direct orindirect communication with other RANs that employ the same RAT as theRAN 204 or a different RAT. For example, in addition to being connectedto the RAN 204, which may be utilizing an E-UTRA radio technology, thecore network 206 may also be in communication with another RAN (notshown) employing a GSM radio technology.

The core network 206 may also serve as a gateway for the WTRUs 202 a,202 b, 202 c, 202 d to access the PSTN 208, the Internet 210, and/orother networks 212. The PSTN 208 may include circuit-switched telephonenetworks that provide plain old telephone service (POTS). The Internet210 may include a global system of interconnected computer networks anddevices that use common communication protocols, such as thetransmission control protocol (TCP), user datagram protocol (UDP) andthe internet protocol (IP) in the TCP/IP internet protocol suite. Thenetworks 212 may include wired or wireless communications networks ownedand/or operated by other service providers. For example, the networks212 may include another core network connected to one or more RANs,which may employ the same RAT as the RAN 204 or a different RAT.

Some or all of the WTRUs 202 a, 202 b, 202 c, 202 d in thecommunications system 200 may include multi-mode capabilities, i.e., theWTRUs 202 a, 202 b, 202 c, 202 d may include multiple transceivers forcommunicating with different wireless networks over different wirelesslinks. For example, the WTRU 202 c shown in FIG. 2A may be configured tocommunicate with the base station 214 a, which may employ acellular-based radio technology, and with the base station 214 b, whichmay employ an IEEE 802 radio technology.

FIG. 2B is a system diagram of an example WTRU 202. As shown in FIG. 2B,the WTRU 202 may include a processor 218, a transceiver 220, atransmit/receive element 222, a speaker/microphone 224, a keypad 226, adisplay/touchpad 228, non-removable memory 230, removable memory 232, apower source 234, a global positioning system (GPS) chipset 236, andother peripherals 238. It will be appreciated that the WTRU 202 mayinclude any sub-combination of the foregoing elements while remainingconsistent with an embodiment.

The processor 218 may be a general purpose processor, a special purposeprocessor, a conventional processor, a digital signal processor (DSP), aplurality of microprocessors, one or more microprocessors in associationwith a DSP core, a controller, a microcontroller, Application SpecificIntegrated Circuits (ASICs), Field Programmable Gate Array (FPGAs)circuits, any other type of integrated circuit (IC), a state machine,and the like. The processor 218 may perform signal coding, dataprocessing, power control, input/output processing, and/or any otherfunctionality that enables the WTRU 202 to operate in a wirelessenvironment. The processor 218 may be coupled to the transceiver 220,which may be coupled to the transmit/receive element 222. While FIG. 2Bdepicts the processor 218 and the transceiver 220 as separatecomponents, it will be appreciated that the processor 218 and thetransceiver 220 may be integrated together in an electronic package orchip.

The transmit/receive element 222 may be configured to transmit signalsto, or receive signals from, a base station (for example, the basestation 214 a) over the air interface 216. For example, in oneembodiment, the transmit/receive element 222 may be an antennaconfigured to transmit and/or receive RF signals. In another embodiment,the transmit/receive element 222 may be an emitter/detector configuredto transmit and/or receive IR, UV, or visible light signals, forexample. In yet another embodiment, the transmit/receive element 222 maybe configured to transmit and receive both RF and light signals. It willbe appreciated that the transmit/receive element 222 may be configuredto transmit and/or receive any combination of wireless signals.

In addition, although the transmit/receive element 222 is depicted inFIG. 2B as a single element, the WTRU 202 may include any number oftransmit/receive elements 222. More specifically, the WTRU 202 mayemploy MIMO technology. Thus, in one embodiment, the WTRU 202 mayinclude two or more transmit/receive elements 222 (for example, multipleantennas) for transmitting and receiving wireless signals over the airinterface 216.

The transceiver 220 may be configured to modulate the signals that areto be transmitted by the transmit/receive element 222 and to demodulatethe signals that are received by the transmit/receive element 222. Asnoted above, the WTRU 202 may have multi-mode capabilities. Thus, thetransceiver 220 may include multiple transceivers for enabling the WTRU202 to communicate via multiple RATs, such as UTRA and IEEE 802.11, forexample.

The processor 218 of the WTRU 202 may be coupled to, and may receiveuser input data from, the speaker/microphone 224, the keypad 226, and/orthe display/touchpad 228 (for example, a liquid crystal display (LCD)display unit or organic light-emitting diode (OLED) display unit). Theprocessor 218 may also output user data to the speaker/microphone 224,the keypad 226, and/or the display/touchpad 228. In addition, theprocessor 218 may access information from, and store data in, any typeof suitable memory, such as the non-removable memory 230 and/or theremovable memory 232. The non-removable memory 230 may includerandom-access memory (RAM), read-only memory (ROM), a hard disk, or anyother type of memory storage device. The removable memory 232 mayinclude a subscriber identity module (SIM) card, a memory stick, asecure digital (SD) memory card, and the like. In other embodiments, theprocessor 218 may access information from, and store data in, memorythat is not physically located on the WTRU 202, such as on a server or ahome computer (not shown).

The processor 218 may receive power from the power source 234, and maybe configured to distribute and/or control the power to the othercomponents in the WTRU 202. The power source 234 may be any suitabledevice for powering the WTRU 202. For example, the power source 234 mayinclude one or more dry cell batteries (for example, nickel-cadmium(NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion(Li-ion), etc.), solar cells, fuel cells, and the like.

The processor 218 may also be coupled to the GPS chipset 236, which maybe configured to provide location information (for example, longitudeand latitude) regarding the current location of the WTRU 202. Inaddition to, or in lieu of, the information from the GPS chipset 236,the WTRU 202 may receive location information over the air interface 216from a base station (for example, base stations 214 a, 214 b) and/ordetermine its location based on the timing of the signals being receivedfrom two or more nearby base stations. It will be appreciated that theWTRU 202 may acquire location information by way of any suitablelocation-determination method while remaining consistent with anembodiment.

The processor 218 may further be coupled to other peripherals 238, whichmay include one or more software and/or hardware modules that provideadditional features, functionality and/or wired or wirelessconnectivity. For example, the peripherals 238 may include anaccelerometer, an e-compass, a satellite transceiver, a digital camera(for photographs or video), a universal serial bus (USB) port, avibration device, a television transceiver, a hands free headset, aBluetooth® module, a frequency modulated (FM) radio unit, a digitalmusic player, a media player, a video game player module, an Internetbrowser, and the like.

FIG. 2C is a system diagram of the RAN 204 and the core network 206according to an embodiment. The RAN 204 may be an access service network(ASN) that employs IEEE 802.16 radio technology to communicate with theWTRUs 202 a, 202 b, 202 c over the air interface 216. As will be furtherdiscussed below, the communication links between the differentfunctional entities of the WTRUs 202 a, 202 b, 202 c, the RAN 204, andthe core network 206 may be defined as reference points.

As shown in FIG. 2C, the RAN 204 may include base stations 240 a, 240 b,240 c, and an ASN gateway 242, though it will be appreciated that theRAN 204 may include any number of base stations and ASN gateways whileremaining consistent with an embodiment. The base stations 240 a, 240 b,240 c may each be associated with a particular cell (not shown) in theRAN 204 and may each include one or more transceivers for communicatingwith the WTRUs 202 a, 202 b, 202 c over the air interface 216. In oneembodiment, the base stations 240 a, 240 b, 240 c may implement MIMOtechnology. Thus, the base station 240 a, for example, may use multipleantennas to transmit wireless signals to, and receive wireless signalsfrom, the WTRU 202 a. The base stations 240 a, 240 b, 240 c may alsoprovide mobility management functions, such as handoff triggering,tunnel establishment, radio resource management, traffic classification,quality of service (QoS) policy enforcement, and the like. The ASNgateway 242 may serve as a traffic aggregation point and may beresponsible for paging, caching of subscriber profiles, routing to thecore network 206, and the like.

The air interface 216 between the WTRUs 202 a, 202 b, 202 c and the RAN204 may be defined as an R1 reference point that implements the IEEE802.16 specification. In addition, each of the WTRUs 202 a, 202 b, 202 cmay establish a logical interface (not shown) with the core network 206.The logical interface between the WTRUs 202 a, 202 b, 202 c and the corenetwork 206 may be defined as an R2 reference point, which may be usedfor authentication, authorization, IP host configuration management,and/or mobility management.

The communication link between each of the base stations 240 a, 240 b,240 c may be defined as an R8 reference point that includes protocolsfor facilitating WTRU handovers and the transfer of data between basestations. The communication link between the base stations 240 a, 240 b,240 c and the ASN gateway 242 may be defined as an R6 reference point.The R6 reference point may include protocols for facilitating mobilitymanagement based on mobility events associated with each of the WTRUs202 a, 202 b, 202 c.

As shown in FIG. 2C, the RAN 204 may be connected to the core network206. The communication link between the RAN 204 and the core network 206may defined as an R3 reference point that includes protocols forfacilitating data transfer and mobility management capabilities, forexample. The core network 206 may include a mobile IP home agent(MIP-HA) 244, an authentication, authorization, accounting (AAA) server246, and a gateway 248. While each of the foregoing elements aredepicted as part of the core network 206, it will be appreciated thatany one of these elements may be owned and/or operated by an entityother than the core network operator.

The MIP-HA may be responsible for IP address management, and may enablethe WTRUs 202 a, 202 b, 202 c to roam between different ASNs and/ordifferent core networks. The MIP-HA 244 may provide the WTRUs 202 a, 202b, 202 c with access to packet-switched networks, such as the Internet210, to facilitate communications between the WTRUs 202 a, 202 b, 202 cand IP-enabled devices. The AAA server 246 may be responsible for userauthentication and for supporting user services. The gateway 248 mayfacilitate interworking with other networks. For example, the gateway248 may provide the WTRUs 202 a, 202 b, 202 c with access tocircuit-switched networks, such as the PSTN 208, to facilitatecommunications between the WTRUs 202 a, 202 b, 202 c and traditionalland-line communications devices. In addition, the gateway 248 mayprovide the WTRUs 202 a, 202 b, 202 c with access to the networks 212,which may include other wired or wireless networks that are owned and/oroperated by other service providers.

Although not shown in FIG. 2C, it will be appreciated that the RAN 204may be connected to other ASNs and the core network 206 may be connectedto other core networks. The communication link between the RAN 204 theother ASNs may be defined as an R4 reference point, which may includeprotocols for coordinating the mobility of the WTRUs 202 a, 202 b, 202 cbetween the RAN 204 and the other ASNs. The communication link betweenthe core network 206 and the other core networks may be defined as an R5reference, which may include protocols for facilitating interworkingbetween home core networks and visited core networks. Other network 212may further be connected to an IEEE 802.11 based wireless local areanetwork (WLAN) 260. The WLAN 260 may include an access router 265. Theaccess router may contain gateway functionality. The access router 265may be in communication with a plurality of access points (APs) 270 a,270 b. The communication between access router 265 and APs 270 a, 270 bmay be via wired Ethernet (IEEE 802.3 standards), or any type ofwireless communication protocol. AP 270 a is in wireless communicationover an air interface with WTRU 202 d.

It is desirable to improve passive scanning mechanisms to facilitateFILS and/or to reduce the airtime occupancy of MAC frames used forscanning. The AP may transmit a MAC frame, referred to herein as a “FILSDiscovery (FD) frame,” between full beacon instances to support a quickAP/network discovery for a fast initial link setup. The FD frame may betransmitted periodically and/or non-periodically. If transmittedperiodically, the periodicity of the FD frame may be changed. The FDframe is a public action frame, which may be one of the following: amodified measurement pilot frame, a modified short beacon frame, or anewly designed MAC public action frame.

FD frames may be transmitted as non-HT duplicate physical layerconvergence procedure (PLCP) protocol data units (PPDUs) at 20 MHz ofthe 20, 40, 80, and 160 MHz (given the dynamic frequency selection (DFS)ownership of the transmitter) at the 5 GHz band. The FD frame mayinclude the following information items: SSID, capability, accessnetwork options, security, AP configuration change count (CCC), AP'snext target beacon transmission time (TBTT), and neighbor AP's nextTBTT.

One approach to improve the performance of passive scanning is for theSTA to acquire the AP/network information without sending a proberequest frame. Examples include using a measurement pilot (MP) frame ora short beacon frame.

The MP frame is a compact public action frame transmittedpseudo-periodically by an AP at a shorter interval relative to thebeacon interval. The MP frame provides less information than the beaconframe to allow for the required short interval. The MP frame is used toassist the STA with rapid discovery of the existence of a BSS viapassive scanning, to allow the STA to rapidly collect neighbor AP signalstrength measurements via passive scanning, and to enable the STA totransmit a probe request.

Configuration parameters for a MP frame include the level of support forthe MP and the MP frame interval. FIG. 3 shows an example format of a MPframe 300, which includes a MAC header 302, a frame body 304, and a FCSfield 306. The MAC header 302 includes a frame control field 310, aduration field 312, a destination address field 314, a source addressfield 316, a BSSID field 318, a sequence control field 320, and a HTcontrol field 322.

The frame control field 310 includes a protocol version subfield 330, atype subfield 332, a subtype subfield 334, a to distribution system (DS)subfield 336, a from DS subfield 338, a more fragments subfield 340, aretry subfield 342, a power management subfield 344, a more datasubfield 346, a protected frame subfield 348, and an order subfield 350.

The frame body 304 includes an action frame portion 360, one or morevendor-specific IEs 362, and an optional management message integritycode (MIC) element 364. The action frame portion 360 includes a categoryfield 370, a public action field 372, a capability information field374, a condensed country string field 376, an operating class field 378,a channel field 380, a MP interval field 382, and one or more optionalsub-elements 384. The capability information field 374 includes aspectrum management subfield 390, a short slot time subfield 392, andreserved subfields 394.

The MP frame is broadcast by the AP, and the transmission ispseudo-random. The basic MP interval is smaller than a beacon interval.At each target measurement pilot transmission time (TMPTT) meeting theminimum gap from a TBTT, the AP schedules a MP frame as the next framefor transmission, ahead of other queued frames using the accesscategory-voice (AC_VO) enhanced distributed channel access (EDCA)parameters. The minimum gap between the TMPTT and the TBTT is one halfof the MP interval. At the TMPTT, if the medium is not available for theAP to transmit a MP frame, the AP defers the MP transmission for amaximum period of one MP interval, and drops the delayed MP frametransmission at the next TMPTT.

While the MP frame may serve as a FD frame, it is unsuitable becausemore capability information needs to be carried in the FD frame thanexists in the current MP frame design. This additional capabilityinformation may include, for example: time pointer fields to point to afull/regular TBTT; all the essential information for link setup, so thatthe scanning STA does not need to wait for a regular beacon or a proberequest/response; information on neighbor BSSs, enabling the discoveryof neighbor BSS operating parameters; and information of the FILS beacontransmission time of other BSSs.

A short beacon frame is designed to reduce medium occupancy of thebeacon transmissions, particularly in systems with small channelbandwidths, for example, 1 MHz, 2 MHz, etc., thus resulting in reducedpower consumption (reduced AP transmission time and reduced STAreception time). The short beacon frame is intended to allow a longbeacon interval, for example, 500 ms (five times longer than thecommonly used 100 ms beacon interval), but still achieve a quicksynchronization for the STAs that are in a long sleep period and maywake up at a random time, for example, meters/sensors inmachine-to-machine applications.

For the same overhead of a full beacon, the short beacon frame formatallows beacons to be transmitted more often, improving synchronizationtime for asynchronous STAs that wake up at a random time and maysynchronize quickly. The short beacon frame carries only essentialinformation for the primary functions of a beacon, including:advertising the presence of the AP; synchronization of the STAs; sharingthe minimal information required to allow the STA to transmit; and powersaving indications, such as a traffic indication map (TIM). Othernon-essential information may be retrieved during the associationprocess, from a full beacon, or using the probe request/responsemechanism.

FIG. 4 shows an example short beacon frame 400 format, including a framecontrol field 402, a source address (SA) field 404, a timestamp field406, a change sequence field 408, a time of next full beacon field 410,a compressed SSID field 412, an access network options field 414, one ormore optional IEs 416, and a FCS field 418.

The frame control field 402 includes a version subfield 420, a typesubfield 422, a subtype subfield 424, a time of next full beacon presentsubfield 426, a SSID present subfield 428, an interworking presentsubfield 430, a BSS bandwidth subfield 432, a security subfield 434, anda reserved subfield 436. The subfields 426-430 are used to indicatewhether the corresponding field 410-414 (as shown by the dashed arrowsin FIG. 4) is present in the short beacon frame 400.

The requirements of the short beacon frame include a minimum frame sizeof 17 bytes, with the following information fields: BSS bandwidth, SA,timestamp, and change sequence value. The short beacon frame may alsoinclude optional information fields, such as three-bit indicators forthe frame control (FC) field to indicate the time of the next fullbeacon, compressed SSID, and access network options; and optional IEswith variable sizes.

The short beacon frame format may not be suitable for use with the FDframe, because the use cases under which the short beacon frame wasdesigned are different from the FD frame use cases. The short beaconframe use cases include both non-associated STAs (for example, metersand sensors with long sleep cycles) and associated STAs, and do not haveto support legacy STAs. Very high wireless medium occupancy may beexpected due to lower transmission rates (as low as 100 kbps) withsmaller channel sizes and a longer beacon interval. Furthermore, the FDframe use cases include primarily non-associated STAs, requirecompatibility with legacy STAs, and work with more conventional channelsizes. In addition, the different use cases support different framecontents. With the short beacon frame, it is important to include“change sequence” information and it requires TIMs for associated STAs,but the FD frame use cases do not require a “change sequence” value orsupport for a TIM.

The current MAC frame format presents a challenge in designing the FILSDiscovery (FD) frame, because of the goals of minimizing the FD framesize and allowing legacy non-AP STAs to coexist with FILS-capable non-APSTAs in FILS-capable AP based WLAN systems.

One of the FD frame design goals is to reduce wireless medium occupancy,which requires the FD frame have a small size, preferably smaller thanthe beacon frame. For example, based on a WLAN system trafficmeasurement study, the typical beacon frame body size is about 130bytes, thus the FD frame body is desired to be less than 50 bytes. Thisimposes two design challenges: identify the necessary information foreach content item in the FD frame and efficiently support variablelength information items and optional information items in the FD frame.

Currently, the information element (IE) is the most commonly used formatto encode variable length information items and optional informationitems. There is a two-byte overhead for each IE: an element ID field(one byte) and a length field (one byte). The IE also includes aninformation body field whose size is specified by the length field. Withthe FILS Discovery mandatory and optional content items, seven IEs areneeded (14 bytes of encoding overhead), including the SSID (a variablelength information item) and six other optional information items.Therefore, alternative encoding schemes are needed in the FD frame tosupport variable length information items and optional informationitems.

The following information may be included in the FD frame to facilitatefast AP/network selection: time to next TBTT, capabilities information,BSS load information, security information, access network options, andneighbor AP information.

The TBTT information is currently provided as a time value based on acommon clock synchronized between the AP and the STA. For example, thenext TBTT may be derived from two parameters in the regular beaconframe: an eight byte timestamp and a two byte beacon interval field. Thetimestamp information necessary for the next TBTT is provided by athree-byte Next TBTT Time information field, using the three leastsignificant bytes of the AP's timestamp. Synchronization is neededbetween the AP and the STA for the STA to correctly interpret the nextTBTT time information, when a time value based on the commonsynchronized clock is used. Because the FD frame is intended to be thefirst frame received by a STA during initial link setup, thetimestamp-based parameter is not applicable to indicate the next TBTTinformation in the FD frame. Alternative method(s) are required toaddress these shortcomings.

An indication of the time to the next TBTT indicates the arrival time ofthe next regular full beacon frame from the transmitting AP of thecurrent FD frame. The indication uses one byte, in a number of timeunits (TUs), i.e., 1024 μs. The offset value is referenced from thecurrent FD frame transmission time.

The capabilities information assists the STA in fast AP/networkdiscovery and includes, but is not limited to, PHY capabilityindications, for example, a short preamble or a packet binaryconvolutional code (PBCC); security capability indications; an ESSindicator; a short time slot; spectrum management information; and anIP4/IPv6 indication.

Most of the existing BSS load information may not be required by a BSS.Therefore, a simple indication of the AP/BSS load may be used. Forexample, the current load of the AP/BSS may be compressed into a fieldas short as one byte long and includes channel utilization, averageaccess delay, and/or other measures that accurately reflect the currentAP load. One or two parameters may be sufficient to signal the BSS load.In one implementation, a one byte field for either the average accessdelay or the channel utilization may be used. In another implementation,a one byte field for both the average access delay and the channelutilization may be used, with five bits used for the average accessdelay and three bits used for the channel utilization.

The security information may include a robust security network element(RSNE), which may be represented by two to four octets, and a privacycapability indication.

Other security information considerations may be addressed by includingadditional FILS fields. For example, the AP may advertise that itsupports optimized FILS authentication procedures, such as FILSExtensible Authentication Protocol (EAP) and/or FILS non-EAPauthentication. The AP's support of FILS authentication procedures maybe flagged using bits in the RSNE capabilities field. In such a case, anadditional field may be added to the RSNE to carry the additionalattributes of the specific FILS authentication procedure (for example,FILS identity, cryptographic suites, etc.).

The access network options indicate access services provided by theAP/network (including the access network type). FIG. 5 shows an accessnetwork options (ANO) IE 500 format that may be used to signal thisinformation in the FD frame. The access network options IE 500 includesan access network type field 502, an Internet field 504, an additionalstep required for access (ASRA) field 506, an emergency servicesreachable (ESR) field 508, and an unauthenticated emergency serviceaccessible (UESA) field 510.

A neighbor AP is currently identified using its BSSID (six bytes) orSSID (typically six to eight bytes, but could be as large as 32 bytes).When there are multiple neighbor APs, the neighbor AP information itemsneed to be organized in the FD frame such that the effectiveness ofincluding the neighbor AP information in the FD frame may be achievedwith the minimum necessary information included.

The neighbor AP information provides information about neighborAPs/channels, and includes the channel class, the channel number, thenext TBTT, and possibly the BSSID or the SSID. FIG. 6 shows an exampleof a neighbor AP IE 600 for use in the FD frame. The neighbor AP IE 600includes an element ID field 602, a length field 604, and informationfor each neighbor AP 606. The information for a neighbor AP 606 includesan operation class field 610, an operation channel field 612, and a timeto next TBTT field 614.

The following information may be included in the FD frame to advertisethe presence of an AP: BSSID, compressed SSID, and channel descriptors.The BSSID uniquely identifies each BSS and is a six byte MAC address ofthe AP for an infrastructure BSS. The information in the BSSID may becarried in the SA (source address) field or the Address-3 field in theMAC header of the FD frame.

The compressed SSID includes the identity of an extended service set(ESS) or an independent basic service set (IBSS). A device that knowsthe full SSID may discover the presence of the BSS by decoding thecompressed SSID. A standardized hashing function may be performed on theSSID to create the compressed SSID. In one implementation, thecompressed SSID field is four bytes long.

The channel descriptors include the channel frequency and spacing forthe operating channel, specified by country, operation class, andoperation channel. The country string identifies the country in whichthe STA is operating, and a condensed country string (for example, thefirst two bytes in the country string) may be used for the FD frame. Theoperation class identifies the operation class for the operationchannel. The operation channel identifies the operation channel withinthe operation class.

The shortened timestamp used for the short beacon frame (the four leastsignificant bytes of the timestamp at the AP) may be reused for the FDframe.

Several versions of optimizing the robust security network element(RSNE) are described in FIGS. 7-12. FIG. 7 shows an RSNE 700 format,including an element ID field 702; a length field 704; a version field706; a group data cipher suite field 708; a pairwise cipher suite countfield 710; a pairwise cipher suite list field 712, where m denotes thepairwise cipher suite count; an authentication and key management (AKM)suite count field 714; an AKM suite list field 716, where n denotes theAKM suite count; a RSN capabilities field 718; a pairwise master key(PMK) identifier (PMKID) count field 720; a PMKID list field 722, wheres denotes the PMKID count; and a group management cipher suite field724. The RSNE may be up to 255 octets in length, and RSNE optimizationis required for it to be included into the FD frame.

FIG. 8 shows an optimized RSNE 800 for use in the FD frame using afixed-length four octet coding. The RSNE 800 includes a group datacipher suite field 802, which may be four bits long; a pairwise ciphersuite list field 804, which may be eight bits long, allowing up to twopairwise suites; an AKM suite list field 806, which may be eight bitslong, allowing up to two AKM suites; an optimized RSN capabilities field808, which may be eight bits long; and a group management cipher suitefield 810, which may be four bits long. The RSN capabilities field 808may include a one bit pre-authentication subfield and a one bitmanagement frames protection required subfield. The remaining six bitsof the RSN capabilities field 808 may carry other information, includingflags for AP support of FILS authentication procedures; for example, aone bit FILS EAP authentication field and a one bit FILS non-EAPauthentication field.

FIG. 9 shows an optimized RSNE 900 for use in the FD frame using avariable-length coding of up to four octets. The RSNE 900 includes agroup data cipher suite field 902, which may be four bits long; apairwise cipher suite count field 904, which may be two bits long; apairwise cipher suite list field 906, which may be zero, four, or eightbits long, depending on the value of the pairwise cipher suite countfield 904; an AKM suite count field 908, which may be two bits long; anAKM suite list field 910, which may be zero, four, or eight bits long,depending on the value of the AKM suite count field 908; an optimizedRSN capabilities field 912, which may be four bits long; and a groupmanagement suite field, which may be four bits long. The RSNcapabilities field 912 may include a one bit pre-authenticationsubfield, a one bit management frames protection required subfield, aone bit FILS EAP authentication subfield, and a one bit FILS non-EAPauthentication subfield.

FIG. 10 shows an optimized RSNE 1000 for use in the FD frame using afixed-length bit map coding of four octets. The RSNE 1000 includes agroup data cipher suite field 1002, which may be four bits long; apairwise cipher suite list field 1004, which may be eight bits long,allowing up to eight pairwise suite selections; an AKM suite list field1006, which may be eight bits long, allowing up to eight AKM suiteselections; an optimized RSN capabilities field 1008, which may be eightbits long; and a group management suite field, which may be four bitslong. The RSN capabilities field 1008 may include a one bitpre-authentication subfield and a one bit management frames protectionrequired subfield. The remaining six bits of the RSN capabilities field1008 may carry other information, reflecting AP support of FILSauthentication procedures.

FIG. 11 shows an optimized RSNE 1100 for use in the FD frame using afixed-length two octet coding. The RSNE 1100 includes a combined groupand pairwise cipher suite field 1102, which may be four bits long; anAKM suite list field 1104, which may be four bits long; an optimized RSNcapabilities field 1106, which may be four bits long; and a groupmanagement suite field 1108, which may be four bits long. The pairwisecipher suite field 1102 represents the cipher suite selected to be usedto protect both group data and pairwise data. The RSN capabilities field1106 may include a one bit pre-authentication subfield, a one bitmanagement frames protection required subfield, a one bit FILS EAPauthentication subfield, and a one bit FILS non-EAP authenticationsubfield.

FIG. 12 shows an alternative optimized RSNE 1200 for use in the FD frameusing a fixed-length two octet coding. The RSNE 1200 includes a groupcipher suite field 1202, which may be four bits long; a pairwise ciphersuite list field 1204, which may be four bits long; an AKM suite listfield 1206, which may be four bits long; and a group management ciphersuite field 1208, which may be four bits long. In the RSNE 1200, the RSNcapabilities field is not included in the FD frame.

In the RSNEs 700-1200, the cipher suites may be represented by four bitsas shown in Table 1.

TABLE 1 OUI Four bit (organizationally representation unique Suite ofcipher suite identifier) type Meaning 0000 00-0F-AC 0 Use group ciphersuite 0001 00-0F-AC 1 WEP-40 0010 00-0F-AC 2 TKIP 0011 00-0F-AC 3Reserved 0100 00-0F-AC 4 CCMP - default pairwise cipher suite anddefault group cipher suite for data frames in an RSNA 0101 00-0F-AC 5WEP-104 0110 00-0F-AC 6 BIP - default group management cipher suite inan RSNA with management frame protection enabled 0111 00-0F-AC 7 Groupaddress traffic not allowed 00-0F-AC 8-255 Reserved Vendor OUI OtherVendor-specific Other Any Reserved

In the RSNEs 700-1200, the AKM suites may be represented by four bits asshown in Table 2.

TABLE 2 AKM Meaning suite Key list Suite derivation bits OUI typeAuthentication type Key management type type 0000 00-0F- 0 ReservedReserved Reserved AC 0001 00-0F- 1 Authentication RSNA key managementDefined in AC negotiated over IEEE as defined in 11.6 or 11.6.1.2 802.1Xor using using PMKSA caching PMKSA caching as as defined in 11.5.9.3 -defined in 11.5.9.3 - RSNA default RSNA default 0010 00-0F- 2 PSK RSNAkey management Defined in AC as defined in 11.6, using 11.6.1.2 PSK 001100-0F- 3 FT authentication FT key management as Defined in AC negotiatedover IEEE defined in 11.6.1.7 11.6.1.7.2 802.1X 0100 00-0F- 4 FTauthentication using FT key management as Defined in AC PSK defined in11.6.1.7 11.6.1.7.2 0101 00-0F- 5 Authentication RSNA Key ManagementDefined in AC negotiated over IEEE as defined in 8.5 or 11.6.1.7.2802.1X or using using PMKSA caching PMKSA caching as as defined in11.5.9.3, defined in 11.5.9.3 with with SHA256 Key SHA256 Key DerivationDerivation 0110 00-0F- 6 PSK with SHA256 Key RSNA Key Management Definedin AC Derivation as defined in 11.6 using 11.6.1.7.2 PSK with SHA256 KeyDerivation 0111 00-0F- 7 TDLS TPK Handshake Defined in AC 11.6.1.7.21000 00-0F- 8 SAE Authentication RSNA key management Defined in AC withSHA-256 or using as defined in 11.6, 11.6.1.7.2 PMKSA caching as PMKSAcaching as defined in 11.5.9.3 with defined in 11.5.9.3 with SHA-256 keyderivation SHA256 key derivation or authenticated mesh peering exchangeas defined in 13.5 1001 00-0F- 9 FT authentication over FT keymanagement Defined in AC SAE with SHA-256 defined in 11.6.1.7 11.6.1.7.200-0F- 10-255 Reserved Reserved Reserved AC Vendor Any Vendor-specificVendor-specific Vendor- OUI specific Other Any Reserved ReservedReserved

The following information may be included in the FD frame to enable theSTA to transmit, including PHY specific information and powerconstraints. The PHY specific information includes 802.11g, 802.11n, and802.11ac PHY-specific information. The 802.11g PHY-specific informationincludes three bits (NonERP_Present, Use_Protection, andBarker_Preamble_Mode) from the extended rate PHY (ERP) IE. The fivereserved bits may be used to signal other information in thecapabilities field.

The 802.11n PHY-specific information may include a shortened HTcapabilities element which may be compressed into a one byte informationbody as shown in Table 3.

TABLE 3 HT Capabilities Item Size (bits) Supported Channel Width Set 1HT-Greenfield 1 Transmit STBC 1 Receive STBC 2 Reserved 2 40 MHzIntolerant 1

The 802.11n PHY-specific information may also include a shortened HToperation element which may be compressed into a one byte informationbody, using only the primary channel field. Optionally, the one bit STAchannel width subfield may be included, and one reserved bit in Table 3may be reused to save overhead.

FIG. 13 shows an example of a HT PHY-specific IE 1300 for use in the FDframe. The HT PHY-specific IE 1300 includes a supported channel widthset field 1302, to indicate the channel widths supported by the STA; anHT-Greenfield field 1304, to indicate support for receiving PPDUs withthe HT-Greenfield format; a transmit space-time block coding (STBC)field 1306, to indicate support for the transmission of PPDUs usingSTBC; a receive STBC field 1308, to indicate support for receiving PPDUsusing STBC; a reserved portion 1310; a 40 MHz intolerant field 1312, toindicate whether 40 MHz transmissions are prohibited; and a primarychannel field 1314, to indicate the primary operating channel.

The 802.11ac PHY-specific information may include a shortened VHTcapabilities element which may be compressed into a one byte informationbody as shown in Table 4.

TABLE 4 VHT/HT Capabilities and Operation Item Size (bits) SupportedChannel Width Set (from 2 VHT Capability Element) Transmit STBC (fromVHT Capability 1 Element) Receive STBC (from VHT Capability 3 Element)STA Channel Width (from HV 1 Operation Element) Reserved 1

The 802.11ac PHY-specific information may also include a shortened VHToperation element, and a HT operation element which may be compressedinto a four byte information body.

The BSS operating channel width may be indicated by a combination of theSTA channel width subfield in the HT operation element HT operationinformation field and the channel width subfield in the VHT operationelement VHT operation information field. The STA channel width subfieldmay be packed with other items in the one byte information body as shownin Table 4 above.

The channelization may be indicated by using a combination of theinformation in the HT operation element primary channel field and theVHT operation element VHT operation information field channel centerfrequency segment 0 and channel center frequency segment 1 subfields.

FIG. 14 shows an example of a VHT PHY-specific IE 1400 for use in the FDframe. The VHT PHY-specific IE 1400 includes a first portion 1402 withelements compressed from the VHT capabilities element, a second portion1404 with elements compressed from the HT operation element, and a thirdportion 1406 with elements from the VHT operation element. The firstportion 1402 includes a supported channel width set field 1410, atransmit STBC field 1412, and a receive STBC field 1414. The secondportion 1404 includes a STA channel width field 1416, a reserved portion1418, and a primary channel field 1420. The third portion 1406 includesa channel width field 1422, a channel center frequency segment 0 field1424, and a channel center frequency segment 1 field 1426.

The power constraints information includes the information necessary toallow a STA to determine the local maximum transmit power in the currentchannel. The one byte power constraints IE in the beacon or the proberesponse frame may be reused to signal this information in the FD frame.

A control field, called the FD frame control field, is introduced intothe FD frame to support an efficient encoding of the content items inthe FD frame body. FIG. 15 shows an example of a FD frame 1500 includinga FD frame header 1502, a FD frame body 1504, and a FCS field 1506. TheFD frame header 1502 may include a MAC management frame header and otherframing fields, depending on the frame format used. The FD frame body1504 includes a FD frame control field 1510 and the FD frame contents1512.

The FD frame control field 1510 may be located in any deterministicplace in the FD frame body 1504, as long as the STA receiving the FDframe 1500 can locate the control field unambiguously. In oneimplementation, the FD frame control field 1510 may be placed as thefirst information field in the FD frame body 1504.

The FD frame control field 1510 includes one or more controlsubfield(s), which are used to support the receiving STA indeterministically decoding and interpreting the content items in the FDframe body 1504. Typical examples include indicating the presence of theoptional information items in the FD frame body 1504 and accommodatingvariable-size information items in the FD frame body 1504. In oneimplementation, the FD frame control field 1510 may include a one bitindicator to indicate whether or not an optional content item is presentin a specific FD frame instance. Using the one bit indicator is a moreefficient encoding scheme compared to the IE format with its two byteencoding overhead. The FD frame control field 1510 collects all of theneeded control information for the content items in the FD frame body1504 into a single control field, while the IE format distributes thecontrol information into each content item.

The SSID information is required in the FD frame to allow the AP toadvertise its presence on the channel and to enable a STA to initiateassociation. It is noted that the SSID information is the onlyinformation that is required to be in the FD frame, and any additionalinformation items included in the FD frame are optional. Currently, thefull SSID (which is zero to 32 bytes long) is needed to initiateassociation. During initial link setup, the SSID information is providedto the STA in the beacon and probe response frames, encoded in the SSIDIE.

While the maximum size of the SSID is 32 bytes, in practice, SSIDsusually have a smaller size, for example, typically six to eight bytes.A variable length SSID information item may be supported in the FDframe. A separate control subfield may be included in the FD framecontrol field to signal the actual size of the SSID in the FD frameinstead of using the SSID IE format. To minimize the size of the FDframe, the SSID information item in the FD frame may be sent in acondensed format, for example, compressed, truncated, etc.

FIGS. 16A-16B show two examples of the SSID information item design forthe FD frame. FIG. 16A shows a FD frame 1600 including a FD frame header1602, a FD frame body 1604, and a FCS field 1606. The FD frame header1602 may include a MAC management frame header and other framing fields,depending on the frame format used. The FD frame body 1604 includes a FDframe control field 1610, a SSID field 1612, and other information items1614 for the FD frame. It is noted that the other information items 1614are optional, and in some embodiments, only the SSID field 1612 may beincluded in the FD frame body 1604.

The FD frame control field 1610 includes a SSID length field 1620 andother control subfields 1622. The SSID length field 1620 is used toindicate the actual size, in bytes, of the SSID field 1612. In thisembodiment, the SSID retains the typical size range, i.e., zero to 32bytes.

FIG. 16B shows a FD frame 1650 including a FD frame header 1652, a FDframe body 1654, and a FCS field 1656. The FD frame header 1652 mayinclude a MAC management frame header and other framing fields,depending on the frame format used. The FD frame body 1654 includes a FDframe control field 1660, a SSID field 1662, and other information items1664 for the FD frame. It is noted that the other information items 1664are optional, and in some embodiments, only the SSID field 1662 may beincluded in the FD frame body 1654.

The FD frame control field 1660 includes a SSID indicator subfield 1670,a SSID length subfield 1672, and other control subfields 1674. The SSIDindicator subfield 1670 is used to indicate if the SSID field 1662contains a full SSID or a condensed SSID, and may be implemented as aone bit indicator. The SSID length subfield 1672 is used to indicate thelength, in bytes, of the SSID field 1662. In this implementation, theSSID is presented in a truncated range, for example, from zero to eightbytes.

Because a full SSID is required for the STA to initiate association, anycondensed SSID (which may include a compressed SSID or a truncated SSID,for example) needs to be deterministically mapped back to its full SSID.There are several options to condense or compress the SSID at thetransmitter side, and there are several options to map or decompress theSSID at the receiver side. The specific options chosen do not affect thecontents of the FD frame 1650.

The capability information item in the FD frame includes the followingfeatures. It includes a minimum set of necessary AP/network capabilityinformation that is needed for the STA to de-select an AP/network duringAP/network discovery in initial link setup. The existing two bytecapability field may be modified to be used in this context as startingpoint, and removes unnecessary subfields for FD frame use. FD framerelevant information items are added, for example, supported minimumrate, PHY type, PHY mode(s), IPv4/IPv6 support, etc. A one bit indicatorin the FD frame control field may be used to indicate the presence ofthe capability information item in the FD frame.

FIG. 17 shows an example of an FD frame 1700 including a three byte longFD capability information item. The FD frame 1700 includes a FD frameheader 1702, a FD frame body 1704, and a FCS field 1706. The FD framebody 1704 includes a FD frame control field 1710, a SSID field 1712, aFD capability field 1714, and other information items 1716. It is notedthat the other information items 1716 are optional, and in someembodiments, the other information items 1716 may be omitted from the FDframe body 1704.

The FD frame control field 1710 includes a SSID length subfield 1720; acapability presence indicator field 1722, to indicate whether the FDcapability field 1714 is present in the FD frame 1700; and other controlsubfields 1724.

The FD capability field includes an ESS subfield 1730, an IBSS subfield1732, a contention free (CF) pollable subfield 1734, a CF-Poll requestsubfield 1736, a privacy subfield 1738, a short preamble subfield 1740,an Internet Protocol (IP) v4 support subfield 1742, an IPv6 supportsubfield 1744, a spectrum management subfield 1746, a QoS subfield 1748,a short slot time subfield 1750, a first reserved subfield 1752, a radiomanagement subfield 1754, a second reserved subfield 1756, a delayedblock ACK subfield 1758, an immediate ACK subfield 1760, a PHY typesubfield 1762, and a supported minimum rate subfield 1764.

Based on the features described above, alternative designs of the FDcapability field 1714 may be generated. For example, the supportedminimum rate subfield 1764 may be eliminated, assuming that thisinformation may be inferred from the PHY type subfield 1762 as theminimum mandatory rate. In addition, the supported minimum rate subfield1764 may be encoded as numerical values at pre-defined units, forexample, at steps of 0.5 Mbps, 1 Mbps, etc.

The CF pollable subfield 1734 and the CF-Poll request subfield 1736 maynot be needed in the FD capability field 1714, because the QoS subfield1748 may provide sufficient information for the AP/network initialde-selection purposes.

The ACK related capabilities, for example, the delayed block ACKsubfield 1758 and the immediate ACK subfield 1760, may be signaled in alater message during link setup instead of in the first AP to STAmessage, such as the FD frame 1700. This allows the two FD capabilitybits for the delayed block ACK and the immediate ACK to be “reserved” orused for other capability indications.

In addition, the bits that are currently reserved in the FD capabilityfield 1714 (for example, the first reserved subfield 1752 and the secondreserved subfield 1756) may be used in the future to indicate new systemcapabilities, for example, a new Layer 3 protocol capability.

The FD security information item may have a fixed length or a variablelength. A fixed length FD security information item may be four byteslong, although any fixed length may be used. A minimum set of necessarysecurity information is included to allow the STA to de-select theAP/network during AP/network discovery in initial link setup. Theexisting RSNE may be modified to make it smaller in size. For example,the RSN capabilities subfield may be redesigned to reflect its practicaluses and the FD frame-specific considerations. The number of pairwisesuites and AKM suites may be limited to, for example, two each. Four bitcodes to identify cipher suites and AKM suites may be used. The PMKIDcount and PMKID list fields may be removed.

The FD security information item may also include security capabilityindicators for FILS authentication methods support, for example, FILSfast-EAP based authentication, FILS EAP-reauthentication protocol (RP)based authentication, FILS non-EAP fast authentication, and FILS fastauthentication without third party. A one bit indicator in the FD framecontrol field may be used to indicate the presence of the securityinformation item in the FD frame.

FIG. 18 shows an example of an FD frame 1800 including a four byte FDsecurity information item. The FD frame 1800 includes a FD frame header1802, a FD frame body 1804, and a FCS field 1806. The FD frame body 1804includes a FD frame control field 1810, a SSID field 1812, a FDcapability field 1814, an access network options (ANO) field 1816, a FDsecurity field 1818, and other information items 1820. It is noted thatthe other information items 1820 are optional, and in some embodiments,the other information items 1820 may be omitted from the FD frame body1804.

The FD frame control field 1810 includes a SSID length subfield 1830, acapability presence indicator field 1832, an ANO presence indicatorsubfield 1834, a security presence indicator subfield 1836, and othercontrol subfields 1838.

The FD security field 1818 includes a group data cipher suite selectorsubfield 1840, a group management cipher suite selector subfield 1842, apairwise cipher suite selector 1 subfield 1844, a pairwise cipher suiteselector 2 subfield 1846, an AKM suite selector 1 subfield 1848, an AKMsuite selector 2 subfield 1850, and a FD RSN capabilities subfield 1852.The FD RSN capabilities subfield 1852 includes a pre-authenticationsubfield 1860, a management frame protection required subfield 1862, aFILS fast EAP subfield 1864, a FILS EAP-RP subfield 1866, a FILS non-EAPsubfield 1868, a FILS authentication without third party subfield 1870,a management frame protection capable subfield 1872, and a perfectforward secrecy subfield 1874.

Based on the features described above, alternative designs of the FDsecurity field 1818 may be generated. For example, if assuming one AKMsuite selector provides sufficient information for the AP/networkinitial de-selection purpose, then the FD security field 1818 maycontain one AKM suite selector, instead of two.

A variable length FD security information item includes similarinformation as the fixed length variant, but with the following changesto reflect its variable length. A variable length security field (RSNE)may be used, and its length may be zero to six octets, for example. Theoptional RSN capabilities (RSNC) subfield within the RSNE field also hasa variable length and may be zero to three octets, for example. Thenumber of pairwise suites and AKM suites may be limited to, for example,up to two each.

FIGS. 19A-19B show an example of an FD frame 1900 including a variablelength FD security information item. The FD frame 1900 includes a FDframe header 1902, a FD frame body 1904, and a FCS field 1906. The FDframe body 1904 includes a FD frame control field 1910, a SSID field1912, a FD capability field 1914, an ANO field 1916, a FD security field1918, and other information items 1920. It is noted that the otherinformation items 1920 are optional, and in some embodiments, the otherinformation items 1920 may be omitted from the FD frame body 1904.

The FD frame control field 1910 includes a SSID length subfield 1930, acapability presence indicator subfield 1932, an ANO presence indicatorsubfield 1934, a security presence indicator subfield 1936, and othercontrol subfields 1938.

The FD security field 1918 includes a RSNE length subfield 1940, a RSNClength subfield 1942, a group data cipher suite selector subfield 1944,a pairwise cipher suite selector 1 subfield 1946, and an AKM suiteselector 1 subfield 1948.

The FD security field 1918 optionally includes a variable length FD RSNcapabilities subfield 1950, a pairwise cipher suite selector 2 subfield1952, an AKM suite selector 2 subfield 1954, and a group managementcipher suite selector subfield 1956. The FD RSN capabilities subfield1950 includes a pre-authentication subfield 1960, a management frameprotection required subfield 1962, a management frame protection capablesubfield 1964, a FILS fast EAP subfield 1966, a FILS EAP-RP subfield1968, a FILS non-EAP subfield 1970, a FILS authentication without thirdparty subfield 1972, a perfect forward secrecy subfield 1974, and areserved subfield 1976.

In FIG. 19B, subfields 1950-1956 and 1976 are shown in dashed outline,to indicate that they are optional items in the FD frame 1900. To theextent that the FD RSN capabilities subfield 1950 is included in the FDframe 1900, subfields 1960-1974 are mandatory, while the reservedsubfield 1976 remains optional.

The TBTT information is generally provided as timestamp value based on acommon clock synchronized between the AP and the STA. But the timestampinformation is not expected to be present in the FD frame. In addition,the FD frame is intended to be the first frame received by a STA ininitial link setup. Therefore, a timestamp-based parameter is not anappropriate method to indicate the next TBTT information in the FDframe.

To signal the next TBTT information without requiring synchronizationbetween the AP and the STA, a one byte offset value of the time offsetbetween the FD frame transmission time and the next beacon frametransmission time may be used, as the FD AP's next TBTT information itemin the FD frame. The offset value is the time in time units (TUs), forexample, 1024 μs. A one bit indicator may be used in the FD framecontrol field to indicate the presence of the AP's next TBTT informationfield in the FD frame.

FIG. 20 shows an example FD frame 2000 including the AP's next TBTTinformation item. The FD frame 2000 includes a FD frame header 2002, aFD frame body 2004, and a FCS field 2006. The FD frame body 2004includes a FD frame control field 2010, a SSID field 2012, a FDcapability field 2014, an ANO field 2016, a FD security field 2018, aconfiguration change count (CCC) field 2020, a FD AP next TBTT (ANT)field 2022, and other information items 2024. It is noted that the otherinformation items 2024 are optional, and in some embodiments, the otherinformation items 2024 may be omitted from the FD frame body 2004.

The FD frame control field 2010 includes a SSID length subfield 2030, acapability presence indicator subfield 2032, an ANO presence indicatorsubfield 2034, a security presence indicator subfield 2036, a CCCpresence indicator subfield 2038, an ANT presence indicator subfield2040, and other control subfields 2042.

A STA that attempts to setup a WLAN link scans a channel and receives aFD frame that contains the transmitting AP's next TBTT information. Ifthe STA still needs further information from the AP, it may use thereceived next TBTT information to make an intelligent decision withregard to what to do next. For example, if the next TBTT informationtells the STA there is a relatively long interval before the next TBTT(for example, more than 50 ms), then the STA may either enter a powersaving state or switch to scan another channel, and then return to thischannel before the next TBTT. If the next TBTT information indicatesthat there will be a beacon frame transmission in a short time interval(for example, less than 20 ms), then the STA may decide to continuemonitoring this channel to receive the next beacon frame or enter apower saving state and return to this channel in time for the nextbeacon frame. In addition, the next TBTT information provided in the FDframe may effectively reduce the number of probe request transmissions.

The FD neighbor AP information item is intended to facilitate fastscanning of multiple APs/channels during initial link setup. There aretwo basic design questions for the FD neighbor AP information item: howto identify a neighbor AP and what information about a neighbor AP isneeded in the FD frame. Similar to the other information items in the FDframe, it is desirable to keep the FD neighbor AP information item smallin size.

The neighbor AP's next TBTT for each neighbor AP is the minimuminformation required in the FD frame. Due to the un-synchronized statebetween the STA and the AP when the FD frame is received, a value fromthe transmitting AP's timestamp or the neighbor AP's timestamp cannot beused to indicate the neighbor AP's next TBTT. Therefore, an offset timevalue between the FD frame transmission time and neighbor AP's TBTT maybe used. The neighbor APs' information may be collected by thetransmitting AP through communications with the neighbor APs or withthird parties, for example, non-AP STAs or other network elements. Whenthe transmitting AP has the proper information about neighbor APs' TBTTsand it decides to include the information in a FD frame transmission, itcalculates the offset value between the FD frame transmission time and aneighbor AP's next TBTT, based on its system clock time value, theestimated FD frame transmission time, and the pre-collected neighborAP's TBTT information.

Two parameters, operating class and channel number, may be used toidentify a neighbor AP. The operating class may be a one byte enumeratedvalue specifying the operating class of the neighbor AP. The channelnumber may be a one byte enumerated value specifying the operatingchannel within the operating class of the neighbor AP.

To provide a sufficient amount of neighbor information while attemptingto keep the size of the FD frame small, the number of neighbors includedin the neighbor AP information item may be limited to, for example, upto two neighbor APs. To indicate the presence of the FD neighbor APinformation item and the number of included neighbor APs, a controlsubfield in the FD frame control field may be used, whose size dependson the maximum allowed number of neighbor APs in the FD neighbor APinformation item. For example, if the maximum allowed number of neighborAPs is k, then an n-bit control subfield is needed, where n is thesmallest integer to satisfy 2^(n)≧(k+1).

FIG. 21 shows an example of a FD frame 2100 including a FD neighbor APinformation item. The FD frame 2100 includes a FD frame header 2102, aFD frame body 2104, and a FCS field 2106. The FD frame body 2104includes a FD frame control field 2110, a SSID field 2112, a FDcapability field 2114, an ANO field 2116, a FD security field 2118, aCCC field 2120, a FD ANT field 2122, a neighbor AP information field2124, and other information items 2126. It is noted that the otherinformation items 2126 are optional, and in some embodiments, the otherinformation items 2126 may be omitted from the FD frame body 2104.

The FD frame control field 2110 includes a SSID length subfield 2130, acapability presence indicator subfield 2132, an ANO presence indicatorsubfield 2134, a security presence indicator subfield 2136, a CCCpresence indicator subfield 2138, an ANT presence indicator subfield2140, a neighbor AP information presence indicator subfield 2142, andother control subfields 2144. The neighbor AP information presenceindicator subfield 2142 is used to indicate whether neighbor APinformation is present and the number of neighbor APs included in theneighbor AP information field 2124.

In one implementation, the neighbor AP information field 2124 includesneighbor AP information for up to two neighbor APs, 2150 a and 2150 b.The neighbor AP information 2150 includes an operating class subfield2152, a channel number subfield 2154, and a next TBTT offset subfield2156. The operating class and the channel number of a neighbor AP may bethe same as the transmitting AP's operating channel, in which case theneighbor AP is operating on the same channel. Similarly, when multipleneighbor APs are included, some of them may have the same parametervalues for operating class and channel number, but with different nextTBTT offset values.

The included neighbor APs may be selected from among all the neighborAPs, based on their next TBTT offsets relative to each other and to thecurrent AP's next TBTT offset. For example, with up to two neighbor APs'TBTT information, plus the transmitting AP's next TBTT information,there are up to three APs' TBTT information included in a FD frame.Assume that T denotes the typical channel scanning time plus the timeused to switch channels during the scanning process. The two neighborAPs, AP-a and AP-b, may be selected from among the neighbor APs, suchthat AP-a's next TBTT (TBTT-a) and AP-b's next TBTT (TBTT-b) are apartfrom each other and from the transmitting AP's next TBTT with apredefined interval, for example, T. The sum of the offsets between theFD frame transmission time and the next TBTTs of the selected neighborAPs is less than or equal to any other selected neighbor APs.

Other alternative neighbor AP selection schemes may also be used. Forexample, the AP that transmits the FD frame may select the neighbor APsto be included in its FD neighbor AP information item based on theneighbor AP's traffic load, signal strength, security features,capabilities, etc.

In addition to the information items described above, other informationitems may be included in the FD frame, either as mandatory or optionalfields, to provide further information to a STA and allowing the STA toimprove initial link setup. Similarly, a corresponding control subfieldmay be included in the FD frame control field to support decoding andinterpretation of the information items, i.e., whether they are optionalinformation items, and if they are of variable size.

FIG. 22 shows an example of an FD frame 2200. The FD frame 2200 includesa FD frame header 2202, a FD frame body 2204, and a FCS field 2206. TheFD frame body 2204 includes a FD frame control field 2210, a SSID field2212, a FD capability field 2214, an ANO field 2216, a FD security field2218, a CCC field 2220, a FD ANT field 2222, and a neighbor APinformation field 2224.

The FD frame control field 2210 includes a SSID length subfield 2230, acapability presence indicator subfield 2232, an ANO presence indicatorsubfield 2234, a security presence indicator subfield 2236, a CCCpresence indicator subfield 2238, an ANT presence indicator subfield2240, a neighbor AP information presence indicator subfield 2242, andreserved subfields 2244.

The ANO field 2216 may be a one byte field identifying the accessnetwork type, an indication whether the network provides Internetconnectivity, an indication whether the network requires an additionalstep for access, an indication whether emergency services are reachablethrough the AP, and an indication whether unauthorized emergencyservices are reachable through the AP. The AP CCC field 2220 may be aone byte unsigned integer, incrementing every time when the set of APconfiguration parameters changes.

Based on the FD frame body 2204 design in FIG. 22 and assuming a typicalSSID field 2212 of eight bytes, then without any optional informationitems, i.e., with the SSID field 2212 only, the FD frame body 2204 sizeis ten bytes. If all the optional information items (2214-2224) areincluded, the FD frame body 2204 size is 26 bytes, which is also themaximum FD frame body size for a typical SSID.

Based on system traffic measurement, approximately 75% of beacon framesare 158 bytes in length. Since the MAC framing overhead is 28 bytes(including the management frame MAC header and the FCS), a typicalbeacon frame body size is about 130 bytes. Therefore, the FD frame bodyas shown in FIG. 22 is approximately 7.7% of a typical beacon frame bodysize (130 bytes) if no optional information items are included. The FDframe body is 20% of a typical beacon frame body size (130 bytes) if allthe optional information items are included.

The FD frame body design is extensible when additional information itemsare needed in the FD frame. There are two mechanisms to support anextensible FD frame body design. In one option, the available bits inthe FD frame control field are used, which are either the previouslyreserved bits or new bits from extending the size of the FD framecontrol field. In a second option, IEs are used for each informationitem consisting of three components: element ID, length, and body.

FIG. 23 shows an example of an FD frame 2300 with extended informationitems. The FD frame 2300 includes a FD frame header 2302, a FD framebody 2304, and a FCS field 2306. The FD frame body 2304 includes a FDframe control field 2310, a SSID field 2312, a capability field 2314, anANO field 2316, a security field 2318, a CCC field 2320, an ANT field2322, a neighbor AP information field 2324, additional optional fields2326, and optional IEs 2328.

With the FD frame body extensibility, the AP may flexibly includeadditional information items in the FD frame to facilitate FILS and/orreduce the number of probe request/response frame transmissions. Oneexample of the additional optional information items may be timesynchronization information, for example, a full timestamp value or someform of condensed timestamp information. Another example is BSS loadinformation, either using the existing BSS load related IEs orintroducing a new optional information field or element with enhancedBSS load information selections and encodings.

The FD frame may be designed as a public action frame or an extensionframe. The public action frame is a MAC management frame. There are someunused codes in the “public action field” which are currently reserved.A new public action frame may be defined by using one of the reservedcodes. FIG. 24 shows an example of encoding a FD frame 2400 as a newpublic action frame, where the public action field=16 is assigned to theFD frame 2400.

The FD frame 2400 includes a MAC header 2402, a frame body 2404, and aFCS field 2406. The MAC header 2402 includes a frame control field 2410,a duration/ID (DU) field 2412, a destination address field 2414, asource address field 2416, a BSSID field 2418, a sequence control (SC)field 2420, and a HT control (HTC) field 2422. The frame body 2404includes an action field 2430, one or more optional vendor-specific IEs2432, and an optional management message integrity code (MIC) element2434.

The action field includes a category field 2440, a public action field2442, a FD frame control field 2444, a SSID field 2446, a capabilityfield 2448, an ANO field 2450, a security field 2452, a CCC field 2454,an ANT field 2456, and a neighbor AP information field 2458. The FDframe control field 2444 includes a SSID length subfield 2460, acapability presence indicator subfield 2462, an ANO presence indicatorsubfield 2464, a security presence indicator subfield 2466, a CCCpresence indicator subfield 2468, an ANT presence indicator subfield2470, a neighbor AP information presence indicator subfield 2472, andreserved subfields 2474.

An 802.11g-based MAC header is used in FIG. 24, for demonstrationpurposes. In 802.11n WLAN systems with HT_GF or HT_MF PPDUs, a four byteHT control field is also included in the MAC header of MAC managementframes.

The extension frame is a MAC frame type which uses the type=0b11 in theframe control field of the MAC header. With a four bit subtype field,there are up to 16 extension frames that may be defined. One availablesubtype value of the extension frame, for example, subtype=0b0010, maybe used to define the FD frame as a new extension frame.

Multiple alternative detailed MAC framing designs are possible for theFD extension frame, including a separate frame control (FC) field and aspecific FD frame control field and a combined FC field. One differencebetween these designs is how the frame control information is organized,particularly, whether or not the general frame control information andFD frame-specific control information are separated or combined.

FIG. 25 shows a FD frame 2500 design with a separate FC field and a FDframe specific frame control field (FD FC). The FD frame 2500 includes aMAC header 2502, a frame body 2504, and a FCS field 2506. The MAC header2502 includes a frame control field 2510, a source address field 2512,and a HTC field 2514. The source address field 2512 contains the MACaddress of the transmitting STA of the FD frame, which is also the BSSIDof the AP STA of an infrastructure BSS. In one implementation, thesource address field 2512 is six bytes long. The frame control field2510 includes a protocol version subfield 2520, a type subfield 2522, asubtype subfield 2524, a reserved portion 2526, and an order subfield2528. The order subfield 2528 is used to indicate if HTC is present.

The frame body 2504 includes a FD frame control field 2530, a SSID field2532, a FD capability field 2534, an ANO field 2536, a FD security field2538, a CCC field 2540, an ANT field 2542, and a neighbor AP informationfield 2544. The FD frame control field 2530 includes a SSID lengthsubfield 2550, a capability presence indicator subfield 2552, an ANOpresence indicator subfield 2554, a security presence indicator subfield2556, a CCC presence indicator subfield 2558, an ANT presence indicatorsubfield 2560, a neighbor AP information presence indicator subfield2562, and reserved subfields 2564.

The first byte of the frame control field 2510 in the MAC header 2502 isthe generic frame control (FC) field of the FD extension frame, which isof the same format as the first byte of other MAC frames, includingmanagement frames, control frames, and data frames. Using this format isimportant for a receiving STA to identify a received frame using theinformation in the frame control field, for example, type and subtype.If it is a known frame type, then the receiving STA may use the framecontrol information to decode the rest of the received frame. If it isan unknown frame type, the receiving STA skips over the frame using thelength information given in the PLCP header or MPDU delimiter in anaggregate MPDU (A-MPDU).

The second byte of the frame control field 2510 is also generic, andcontains the order subfield 2528, which is used to indicate whether afour byte HTC field is present. The other seven bits in the second byteof the frame control field 2510 are reserved or may be used for otherpurposes, because the original subfields do not apply for the FD frame.

FIG. 26 shows a FD extension frame 2600 design with a combined framecontrol field with generic frame control information and FD framespecific frame control information. The FD frame 2600 includes a MACheader 2602, a frame body 2604, and a FCS field 2606. The MAC header2602 includes a frame control field 2610, a source address field 2612,and a HTC field 2614.

The frame control field 2610 includes a protocol version subfield 2620,a type subfield 2622, a subtype subfield 2624, a HTC presence indicatorsubfield 2626, a SSID length subfield 2628, a capability presenceindicator subfield 2630, an ANO presence indicator subfield 2632, asecurity presence indicator subfield 2634, a CCC presence indicatorsubfield 2636, an ANT presence indicator subfield 2638, a neighbor APinformation presence indicator subfield 2640, and reserved subfields2642. The first byte of the frame control field 2610 has the same formatas all other MAC frames. It contains the information for a receiving STAto identify the received frame and process it accordingly.

The frame body 2604 includes a SSID field 2650, a FD capability field2652, an ANO field 2654, a FD security field 2656, a CCC field 2658, anANT field 2660, and a neighbor AP information field 2662.

Although features and elements are described above in particularcombinations, one of ordinary skill in the art will appreciate that eachfeature or element may be used alone or in any combination with theother features and elements. In addition, the methods described hereinmay be implemented in a computer program, software, or firmwareincorporated in a computer-readable medium for execution by a computeror processor. Examples of computer-readable media include electronicsignals (transmitted over wired or wireless connections) andcomputer-readable storage media. Examples of computer-readable storagemedia include, but are not limited to, a read only memory (ROM), arandom access memory (RAM), a register, cache memory, semiconductormemory devices, magnetic media such as internal hard disks and removabledisks, magneto-optical media, and optical media such as CD-ROM disks,and digital versatile disks (DVDs). A processor in association withsoftware may be used to implement a radio frequency transceiver for usein a WTRU, UE, terminal, base station, RNC, or any host computer.

What is claimed is:
 1. A method for fast initial link setup (FILS) foruse in a wireless station, the method comprising: receiving a FILSdiscovery (FD) frame from an access point (AP), wherein the FD framecomprises an FD frame control field and FD frame contents, wherein theFD frame contents comprise a service set identifier (SSID) field,wherein the FD frame control field comprises an SSID indicator thatindicates whether the SSID field contains a full SSID or a short SSID,and wherein the FD frame control field comprises an SSID length fieldthat indicates a size of the SSID field; determining to associate withthe AP based on the received FD frame; and transmitting an associationrequest frame to the AP.
 2. The method of claim 1, wherein the FD framecontrol field further comprises: a capability presence indicator,indicating whether an FD capability field is present in the FD framecontents.
 3. The method of claim 1, wherein the FD frame contentsfurther comprises: an FD capability field that comprises an extendedservice set (ESS) subfield, a privacy subfield, a physical layer (PHY)type subfield, and a supported minimum rate subfield.
 4. The method ofclaim 1, wherein the FD frame control field further comprises: an accessnetwork options presence indicator indicating whether an access networkoptions field is present in the FD frame contents; a security presenceindicator indicating whether a security field is present in the FD framecontents; and an AP configuration change count presence indicatorindicating whether an AP configuration change count field is present inthe FD frame contents.
 5. The method of claim 1, wherein the FD framecontents further comprises: an access network options field; a securityfield; and an AP configuration change count field.
 6. The method ofclaim 5, wherein the access network options field indicates an accessservice provided by the AP, the security field indicates one or moretypes of security used by the AP, and the AP configuration change countfield indicates a number of times that a set of AP configurationparameters has changed.
 7. The method of claim 1, wherein the FD frameis received, from the AP, between instances of a beacon frame.
 8. Themethod of claim 1, wherein the short SSID is a condensed format SSID. 9.The method of claim 1, wherein the full SSID is a maximum of 32 bytes.10. The method of claim 1, wherein the short SSID is four bytes.
 11. Awireless station, comprising: a receiver configured to receive a FILSdiscovery (FD) frame from an access point (AP), wherein the FD framecomprises an FD frame control field and FD frame contents, wherein theFD frame contents comprise a service set identifier (SSID) field,wherein the FD frame control field comprises an SSID indicator thatindicates whether the SSID field contains a full SSID or a short SSID,and wherein the FD frame control field comprises an SSID length fieldthat indicates a size of the SSID field; a processor configured todetermine to associate with the AP based on the received FD frame; and atransmitter configured to transmit an association request frame to theAP.
 12. The wireless station of claim 11, wherein the FD frame controlfield further comprises: a capability presence indicator, indicatingwhether an FD capability field is present in the FD frame contents. 13.The wireless station of claim 11, wherein the FD frame contents furthercomprises: an FD capability field that comprises an extended service set(ESS) subfield, a privacy subfield, a physical layer (PHY) typesubfield, and a supported minimum rate subfield.
 14. The wirelessstation of claim 11, wherein the FD frame control field furthercomprises: an access network options presence indicator indicatingwhether an access network options field is present in the FD framecontents; a security presence indicator indicating whether a securityfield is present in the FD frame contents; and an AP configurationchange count presence indicator indicating whether an AP configurationchange count field is present in the FD frame contents.
 15. The wirelessstation of claim 11, wherein the FD frame contents further comprises: anaccess network options field; a security field; and an AP configurationchange count field.
 16. The wireless station of claim 15, wherein theaccess network options field indicates an access service provided by theAP, the security field indicates one or more types of security used bythe AP, and the AP configuration change count field indicates a numberof times that a set of AP configuration parameters has changed.
 17. Thewireless station of claim 11, wherein the FD frame is received, at thereceiver, from the AP, between instances of a beacon frame.
 18. Thewireless station of claim 11, wherein the short SSID is a condensedformat SSID.
 19. The wireless station of claim 11, wherein the full SSIDis a maximum of 32 bytes.
 20. The wireless station of claim 11, whereinthe short SSID is four bytes.